System of distribution.



No. 853,374. BATENTED MAY 14, 1907.

K. o. RANDALL. I

SYSTEM OF DISTRIBUTION urmoumn rum) mu 2. 1906.

Fig. 4.

INVENTOR WlTNESSES: I I

- I ATITORNEY KARL c. RANDALL, F nncnwoon PARK, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORA- TION OF PENNSYLVANIA SYSTEM OF DISTRIBUTION.

Specification of Letters Patent.

Patented May 14,1907.

' Application filed May 2, 1906. .Sarial'No. 314,872.

Tofu/Zi whom it may concern: fBeit knownthatI, KARL C. RANDALL, a citizen of the United States, and a resident of *Erlgewood- Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful In; rovement in- Systems of Distribution, of which the following is a specification.

My'inv'ention relates to systems of electrical distribution and has especial reference to thMe-phaSe-alternating current transforming. and distributing systems. f The object of. my invention is to provide means for balancing the voltage between sec ondary circuits in transformers the primaries andlsecondaries. of which are severally starconnected.

.When three-phase transformers'or three- "single-phasetransformers have been employed for changing-the voltage between'a supply line and a distributin system, it has been usual t0 connect both t e primary andsecondaiywindingsby a delta-connection or at least to; connect either the primary or the Secondary coils in "this'manner, in. order to equalize. the voltage between circuits under varying conditions of load.-. It is sometimesv deslrable, however, to connect both the primary and secondary coils by -star-connec' tion, and in order that the voltage between the circuits may be equalized, in such cases I provide, an auxiliary coil for-each phase of the transformer, or for each transformer, if three single-phase transformers are employed, and delta-connect these coils. With a winding of this character, variations in the voltage between circuits, which are due to] differencesin the .load upon several circuits or to abnormal disturbances in the circuits,

' winding may be applied at such a'sa ground, will be corrected and the currents carried by theauxiliary winding will usuallybe relatively-small so that this small expense.

. Figures 1 and 2 o the accompanying draw ings are diagrammatic views of distributing systems arranged in accordance with my in-- vention.- 1

Referring to Fig. 1 of the drawings, a three phase transformer 1 is provided with starconnectedprimary coils 2, 3 and4, star-connected secondary coils 5, 6 and 7, and delta-' connected auxiliary coils 8, 9 and 10. The coils 2, 5 and 8,4,, fraud- 9", and 3.,fi'and 10 mally closed but which may 15, 1c and 17.

are, respectively, included inthe same magnetic circuit so that three-phase electrical energy may be supplied to the primary coils and energy taken cm the secondary coils for any desired purpose, while theauxiliary coils 8, 9 and 10 carry a relatlvelysmall current which tends to balance the electromotive forces between thev secondary circuits. It is conceivable that the current carried by the auxiliary windingsmay become excessive when serious disturbances occur onthe line supplied by the transformer and this effect maybe used for interrupting either the priby providing a mary or secondary circuits, circuit breaker or interrupter which s noran electrically-operated release magnet included incircuit with the auxiliary coils.

- Referring to Fig. 2, electrical energy is sup plied from a three-phase source llto starconnected primary coils 12, 13 and 14. of a plurality of similar single-phase transformers The transformers are provided with secondary coils 1 8, 19 and 20 which are also star connected. Energy-is supplied from the secondary windings of the transformers 15, 16 and 17 to line" conductors 21, 22 and 23, from which energy may be supplied to translating-* devices 24. -A

be released by circuit interrupter 25 that is adapted to in terr'upt th'e'circuits 21, .22 and 23; comprises a connecting rod 26 and bridging contact members 27, 28 and 29, and may beheld'in its closed position, in opposition to the force of gravity, by a toggle joint 30. A tripping magnet 31' is also provided with an operating coil 32 which breaks the toggle joint and opens the circuit breaker Z5 wheri' the'current flowing through the exceeds a predetermined amount. Th'e'jtransformers 15, 16' and. 17 are further .proztided with deltaco'nnected auxiliary'coils 33, 34 and 35, and the magnet winding 32 is connected in the circuit with, and receives energy from, these winding formers should be lightljr fldiflerent or if the load taken from one phase ofthe'out'going circuit should be greater than that taken- S I, f the electrical performances of the trans.-

ice

from another phase, the electromotive forces between c'onductiers 21", 22 and'23 would become unbalanced,, exce t for the action ,of the auxiliary coils 33, 3,4 and which tend 

